Adding and subtracting device



June 18, 1957 T. J- POOLE ADDING AND SUBTRACTING DEVICE Filed Oct. 31, -l955 :"filf'i i N i an mmvrox.

THO/was J Poo/.5

flTTOENEYJ United States Patent ADDING AND SUBTRACTING DEVICE Thomas J. Poole, Seattle, Wash.

Application October 31, 1955, Serial No. 543,863

4 Claims. (Cl. 3531) This invention relates to educational novelties and it has reference more particularly to a mechanical device or mechanism for the addition and subtraction of numerals. More specifically stated, the present invention has to do with a relatively simple form of mechanism of the above character, that is especially designed for use by children.

It is the principal object of the present invention to provide a relatively inexpensive and easily operable mechanism wherein two rotatably movable elements, each having a column or row of numerals consecutively arranged thereon, are mounted for selective movement, each to expose a selected numeral thereof within a view opening, and wherein a third or answer giving rotatably or movably mounted element, formed with a row or column of numerals thereon, is so aranged and so connected with the moving means for the first mentioned elements, as to be automatically moved to expose, in the viewing opening, the numeral thereon which is the sum of the exposed numerals of the first two elements.

It is a further object of the present invention to provide a mechanism, as above disclosed, that is usable also for the subtraction of numerals.

Yet another object of the invention is to provide a mechanism, of the kind above disclosed, wherein the rotatably mounted and selectively movable elements with the rows or columns of numerals thereon, are in the form of endless belts, operating about driving wheels, and wherein a clutch of novel kind is associated with a drive shaft which provides for selectively and individually driving either of said belts, and which drive shaft has an operative connection with the answer giving element and is operated in conjunction with each of the first mentioned belts.

Still further objects and advantages of the present invention reside in the details of construction and combination of parts, and in their mode of operation as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective view of a mechanism embodying the present invention, with a part of the enclosing housing broken away to disclose the interior mechanism, particularly the belt selecting and moving mechanism.

Fig. 2 is a cross-sectional detail, showing the numeral belt driving means and clutch.

Fig. 3 is a perspective view of certain clutch elements, shown in separated relationship for better understanding.

Referring more in detail to the drawings:

In one of its present preferred forms of construction, as shown in Fig. 1, the mechanism of this invention is shown to comprise a flat, horizontally disposed base plate that is fixed in a box-like enclosing housing, of which said base plate forms the bottom. The housing includes a top wall 11, opposite sidewalls 12 and opposite end walls 13; the top, sides and bottom of the housing prefer- 2,795,816)? Patented June 18, 1957 ably being of sheet metal, and the ends preferably being of wood, or other suitable material.

Mounted on the base plate 10, near the end thereof which in Fig. l is at the left hand side, are laterally spaced brackets 15 which support a horizontal shaft 16 between them. Freely rotatable on the shaft 16 are three belt mounting wheels 17, 18 and 19, all of the same diameter and mounted in rather closely spaced relationship.

Mounted on the base plate 10 at that end of the housing which is opposite that on which the three belt wheels above mentioned are supported, is a rigid frame structure comprising vertically disposed and laterally spaced opposite end plates 2020, and each having an out-turned base flange 21 at its lower end riveted to the base plate, as at 22. At their upper ends, the plates 2020 have out-turned horizontal flanges 23--23' at the same level. Each of the plates 2020' also is formed immediately above its lower end flange with a relatively large cut-out providing an opening 24 and extending horizontally through the openings of these plates, and somewhat beyond the plates as shown in Fig. 2, a flat, horizontal bar 25 is fixed. At its opposite side edges midway of the plates 20-20 this bar is formed with down-turned wings 26.

Extending along the underside of bar 25 and between the wings 26 is a rocker lever 28, pivotally supported by a pin 27 that is extended through the lever and wings. Also, the two laterally spaced plates 20-20 are formed in the upper end portions with round holes 30, through which a shaft 31 is slidably and rotatably extended to the outsides of the plates; this being designated as the drive shaft.

Mounted on the drive shaft 31, in alignment with the belt wheels 17, 18 and 19 at the other end of the housing are belt wheels 34, 35 and 36; all wheels above mentioned being of the same diameter. The shaft 31 has a sliding keyed connection as at 40, with belt wheel 36 for driving the wheel, but the wheels 34 and 35 are freely revoluble on the shaft, except when a driving connection therewith is made through the mediacy of a clutch dog presently to be described.

Extended about aligned wheels, as mounted on the shafts 16 and 31 at opposite ends of the housing, are fiat belts 41, 42 and 43. The belt 43 operates about wheel 36 which is keyed on shaft 31. Therefore, this belt will be moved in opposite directions in accordance with the direction of turning the shaft 31. The other belts, 42 and 43, are adapted to be selectively moved by rotation of their mounting wheels 34 and 35, in accordance with the direction of rotation of shaft 31 when a driving connection is made therewith through the mediacy of a clutch dog now to be described.

It is shown in Figs. 2 and 3, that a cross-head 50 is pinned to shaft 31. At its opposite ends the cross-head has laterally extended teeth 52, as shown best in Fig. 3. The cross-head is mounted on shaft 31 between the wheels 34 and 35 which have openings 54 formed through their web portions, adjacent the rims, as best seen on Fig. 3. By shifting the shaft 31 endwise from one limit of its adjustment to the other, the teeth 52 on the cross-head 50 may be locked in openings of the wheel 34 or of wheel 35, thus to provide a driving connection with the selected wheel.

The selection of the belt 41 or 42 which is to be moved and its movement is made and effected by use of two knobs, or buttons 60 and 61, which are fixedly mounted on the upper ends of vertical shafts 63 and 64 respectively, which extend slidably and rotatably through vertically aligned holes 65 and 66 in the flanges 23 and ends of cross bar 25; the buttons being contained in openings 68 and 69 provided therefor in the top wall 11 of the housing. Fixed on the lower end portions of the vertical shafts 63 and 64, respectively, are gears 71 and 72; these two shafts each being of two diameters, as presently explained. Also, fixed on the opposite ends of the drive shaft 31 are gears 74 and 75 with which the gears 71 and 72 are adapted to be selectively meshed bya proper positioning of the vertically movable shafts 63 and 64, as will now be explained.

. It, is observed in Fig. 2 that the lower end portions of the vertical shafts 63 and 64 are of materially reduced diameter, and at their lower ends they engage, respectively, with opposite end portions of the rocker lever 28. The arrangement is such that when one button is pushed downwardly, it rocks shaft 28 on its pivot 27 to push the. other button upwardly.

The shaft 31 is disposed between the two button mounting shafts 63 and 64; and it is of an exact length that causes it to engage at its opposite ends, as noted in Fig. 2, with the part of larger diameter of one shaft and the part of lesser diameter of the other shaft. The portion of larger diameter of each button mounting shaft merges with the part of lesser diameter in a conically tapered cam surface 78. When a button is depressed, the conical surface portion 78 of its mounting shaft acts against the spherically rounded end surface 31x of shaft 31, and pushes the shaft endwise. This is possible since as one button shaft is pushed down, the other shaft comes up. As shaft 31 is shifted toward one end or the other, the dog 50 locks with the wheel 34 or 35, toward which it moves' Also, when a button 60 or 61 is depressed, it disengages the gear 71 or 72 fixed to its shaft from the driving gear 74 or 75 on shaft 31, and at the same time, inlifting the opposite button, moves its gear 71 or 72 into driving mesh with the driving gear 74 or 75 of shaft 31.

Through the mediacy of the buttons 60 and 61, shaft 31 and dog 50, the numeral belts 41 and 42 can be selectively moved to bring any selected numeral thereon into registration with a viewing opening 80 in the top wall of the housing 11 across which all three belts pass, as shown in Fig. 1.

' The use of the device for adding a numeral on belt 41 with a numeral on belt 42 is as follows: Since the belt wheel 36, which mounts the answer giving belt 43 is slidably keyed to shaft 31, it will be understood that belt 43 will be moved in accordance with the turning of shaft 31. Belts 41 and 42, however, are moved only when the dog 50 locks their respective mounting wheels 34 or 35 to shaft 31. Shifting of belt 42 is effected only by turning button 61.

Now, assuming that numerals are arranged in consecutive order and in the same direction on the three belts, and that the belts are originally with the zero readings in alignment, and that it is desired to add any two numerals, for example, 6 and 10, the button 61 is first depressed. This elevates button 60 to operative position, and simultaneously engages the clutch dog 50 with the driving wheel 34 of belt 41 and engages the gear 71 with the shaft driving gear 74. Then, button 60 is manually rotated to move the belt 41 as required to bring numeral 6 thereon into the viewing opening 80. Then button 60 is depressed, thus bringing button 61 up to its operative position and at the same time engaging the clutch 50 with belt wheel 35, and engaging gear 72 with shaft driving gear 75. Then button 61 is manually rotated to shift the belt 42 as required to bring the numeral 10 into the viewing opening 80. Since the belt 43, which I have referred to as the answer showing belt, moves with the turning of shaft 31, it will be understood that when belt 41 was advanced to bring numeral 6 into the viewing opening, the belt 43 was moved in unison therewith to bring numeral 6 therein into the viewing opening. Then when belt 42 was advanced to bring numeral 10 into the viewing opening, the. belt 43 was also moved an additional ten numeral intervals and thus belt 43 brought numeral 16 into view, this being the answer or sum of the numerals 6 and 10.

Now, without changing the setting of the belts, from that as shown in Fig. 1, should it be desired to add two other numerals, for example, 4 and 8; button 61 is rotated to shift belt 42 to bring numeral 4 into the view opening. Then button 61 is depressed, and button 60 is elevated. Button 60 is then rotated to bring numeral 8 on belt 41 into the view opening. When belt 42 was rotated by button 61 to bring numeral 4 to view, the belt 43 moved to the right accordingly and brought numeral 10'into the view opening. Likewise, when button 60 was rotated to bring numeral 8 into view, the belt 43 was again moved accordingly, to the left and numeral 12 was brought into the view the belt 43 was again moved accordingly to the left and numeral 12 was brought into the view opening; this being the answer or sum of numerals 4 and 8. The direction of movement of the belts might be in either direction, and the final results are the same.

It is understood, of course, that the belt 43, which is the answer showing belt, will have its column of consecutive numerals extended to take care of all sums possible by the adding of numerals on belts 42 and 43.

This same mechanism is adapted also for subtraction merely by a reverse operation.

In the present drawings, I have shown the main housing 11 to enclose both the adding and subtracting means; the buttons 60 and 61, as used for addition, being located at one end of the housing and there being a similar set of buttons designated by numerals 60 and 61 at the opposite end for control of belts whereby subtraction is carried out. The housing also is formed at a suitable location in its top wall with an opening through which the numbers, arranged for subtraction, may be viewed.

It is further to be explained that for the operation of subtraction, numeral carrying belts and the mechanical means for their operation is provided; these parts being exactly like that already described and shown except in the arrangement of numerals on the belts, that is, the numerals on the top belt read consecutively from right to left, the numerals on the middle belt read consecutively from left to right and those on the lower, or answer giving belt read from right to left. The three belts as shownin Fig. l are designated by reference numerals 41', 42' and 43' and they bear the same relationship to each other as do the belts 41, 42 and 43 as used in addition. The belts are initially set with zeros in alignment. The minuend numerals are carried on belt 41', the subtrahend numerals are carried on belt 42' and the answer showing numerals are on belt 43.

To subtract, for example 3 from 5, the button 60 is depressed. Then by means of button 61, the belt 41' is moved to bring numeral 5 into the sight opening. This also moves the belt 43 accordingly. Then button 61 is depressed and button 60' elevated. Then by means of it, the belt 42' is moved to bring the numeral 3 into the sight opening. This causes a like movement of belt 4 3' therewith which brings the numeral 2 into view in the sight opening. Other problems in subtraction are solved in the same manner.

Both in addition and subtraction, the correct answer is obtained by reason of the fact that the lower belt, or answer showing belt, moves with each of the other belts.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

1. A device of the character described comprising a housing formed with a sight opening, a frame structure, a shaft rotatably mounted therein and longitudinally shiftable inopposite directions between definite limits, a series of three belt wheels mounted in adjacent relationship on said shaft and retained by the frame against shifting endwise'with the shaft, belts operable about said wheels and'extended therefrom and through said sight opening for the viewing of numerals thereon, each belt being movable in accordance with the rotation of the wheel about which it passes, numerals formed on each of said belts in consecutive order beginning with Zero, and like spacing, the belt wheel at the lower side of the series being slidably keyed on said shaft, a clutch member fixed on said shaft and selectively engageable with the other of said belt wheels for their rotation by shifting said shaft to its opposite limits, respectively, means for manually shifting said shaft for the engagement of said clutch selectively with the said other belt wheels, and means for effecting the rotation of said shaft for the rotation of the selected wheel to shift its belt to bring a selected numeral thereon into said sight opening; said belt which is mounted on the wheel that is keyed to said shaft being movable with the adjustments of each of said other belts, thus to locate the numeral thereon in the sight opening which is the sum of the numerals on the other belts that are located in said opening.

2. A machine as recited in claim 1 wherein the means for shifting said shaft in opposite directions comprises push buttons fixed on stems that extend transversely through the axial line of said shaft closely adjacent its opposite ends, and on which stems cam surfaces are formed and are adapted, respectively, to engage with the corresponding end of said shaft upon depression of the button to effect an endwise shifting of said shaft in a direction away from the stem axis.

3. A machine as recited in claim 1 wherein the means for shifting said shaft in opposite directions comprises push buttons fixed on stems that extend transversely through the axial line of said shaft closely adjacent its opposite ends, and on which stems cam surfaces are formed and are adapted, respectively, to engage with the corresponding end of said shaft upon depression of the button to effect an endwise shifting of said shaft in a direction away from the stem axis, and wherein a rocker lever is pivotally mounted intermediate its ends, in the plane of said stems, and engaged at its opposite ends with the lower ends of said stems providing that the depression of one button for shifting said shaft automatically lifts the other button from a depressed position and moves its cam surface clear of the shaft end.

4. A machine as recited in claim 3 wherein the means for rotating said shaft comprises, gear wheels fixed on the opposite ends of said shaft, and gear wheels fixed on said button stems and adapted to be selectively engaged by the depression of said buttons with the shaft gears to effect a driving connection between shaft and the raised button.

References Cited in the file of this patent UNITED STATES PATENTS 1,862,435 Schmid June 7, 1932 2,546,641 Llanso Mar. 27, 1951 2,710,142 Stibitz June 7, 1955 

